Half of all Americans over the age of 60 have diverticulosis of the colon, and 20-25% are expected to develop acute diverticulitis. While most episodes resolve with antibiotics alone, 10-20% will have an emergency colectomy/colostomy at their initial presentation and all patients remain at lifetime risk for recurrent episodes. Given te uncertainty of when and where a recurrent episode will occur and the looming risk of colostomy, surgeons have been trained to recommend elective, prophylactic colectomy after 2 episodes, and earlier for those < 50 years. As a result, diverticulitis is now one of the leading reasons for elective colectomy. However, counseling patients after recovering from an episode of diverticulitis is challenging because less than 5% will go on to need emergency surgery and the major morbidity (5%) and recurrence rate (5-11%) after elective resection is not trivial. Several professional societies have now recommended delaying elective resection and called for research to determine its value. Despite these cautions, over the last decade the use of elective resection has increased more than 50%. Elective resections are rising at a much faster rate than the incidence of diverticulitis, coinciding with the widespread adoption of laparoscopy. Given this unexpected trend, it is important to assess the patterns of practice related to early or delayed resection, factors driving decision making, and the impact of the disease on those who do and do not have an elective resection. To address these issues we propose 3 related, but independent studies that describe treatment patterns after recovery from an episode of acute diverticulitis, the factors associated with early and delayed elective surgery, and outcomes and impact of the disease. Aim 1 uses national claims data for a population-level assessment of current patterns of care related to numbers of episodes of treated diverticulitis prior to elective resection. Aim 2 compare how often patients undergoing early versus delayed resection and young vs old report clinical and non-clinical factors as the reason for elective resection. Information from this group about decision making related to elective resection may help explain practice patterns identified in Aim 1. To assess the impact of diverticulitis on all those with the condition, Aim 3 involves a statewide cohort of all patients who recover from an episode of confirmed diverticulitis, assessing how often patients have symptoms related to diverticulitis, patient-reported outcomes, and the burden of the disease over time. Together these studies will determine if the observed, dramatic increase in the use of elective surgery for diverticulitis is consistent with recommendations about delayed intervention, provide better understanding about the factors associated with decisions for elective surgery and provide critical information about the impact of diverticulitis. This information will be helpful in crafting interventions aime at more patient-centered and value-added care and inform decision making. This information will also be critical in the development of comparative studies of colon resection and other treatments for diverticulitis.